KR20120064047A - Angled array sensor method and system for measuring media curl - Google Patents

Abstract

PURPOSE: An inclined array sensor method measuring a media curl having reinforced accuracy for environmentally caused errors is provided to obtain the function of a sheet curl by measuring a point of a propelled media sheet touching an array for an inclined array sensor. CONSTITUTION: An inclined array sensor method measuring a media curl comprises the following steps: propelling more than one curling media sheet toward an inclined array sensor using nibs of a curler(510); locating the inclined array sensor on the upstream or the downstream of a media propelling device in the angle for the media sheets passing through the curler; obtaining the function of a media sheet curl by measuring a point of the propelled media sheet touching an array for the inclined array sensor(530); and accurately determining the sheet curl using the sheet curl function(540).

Description

ANGLED ARRAY SENSOR METHOD AND SYSTEM FOR MEASURING MEDIA CURL}

Embodiments relate generally to rendering devices such as printers, multifunction devices, copiers, fax machines, and the like. Embodiments also relate to curl detection sensors used in connection with rendering devices. Embodiments further relate to the measurement of the leading and trailing edges.

Media curl is frequently considered to be the root cause of paper jam and registration errors that may occur during rendering (eg, printing) operations and may be exacerbated by high density images and multiple color renderings. Media curl can be caused by several factors such as, for example, relative humidity, paper weight, paper size, imaged sides or amount of image. However, sheet curling may also occur with respect to unfringed sheets of paper due to changes in ambient humidity or moisture content of the paper. Seat curls may also be deliberately imposed to improve sheet restraint performance in a sheet transfer system utilizing vacuum or other restraint forces.

Sheet curling may interfere with proper sheet feeding and cause sheet feeding jams, delays, or registration errors. If sheet curl is present at the output, it may interfere with proper lamination or other completion operations. In addition, the amount of moisture in the sheet of paper can vary rapidly from the rendering process itself, causing or worsening curls. The sheet curl problem is also caused by thermal fuser and / or higher density images on one side rather than the other, especially when the sheets are reloaded or recycled to render the imaging material on their second side. In the case of entailing a second transfer of the sheet, it may occur in double-sided printing. The media curl should be measured and controlled so that reliable marking can be achieved and damage to the ink cartridge can be prevented.

Various media curl sensors and control systems are known in the field of electrophotographic rendering. Such prior art systems typically use a multiple beam sensor, such as a single cross beam sensor or a dual cross beam sensor, for example to detect the height / curl of a media sheet. Such beam sensors and their precise placement with respect to nips, delivery belts and media introduce additional opportunities for variability in sensor response characteristics. In addition, these prior art curl measurement schemes tend to be edge error due to air flow, machine vibrations, edge flips, etc., and the measurements are not accurate.

Based on the foregoing, it is believed that there is a need for an improved angled array sensor system and method for accurately measuring leading edge and trailing edge media curl, as described in greater detail herein.

Disclosed herein are systems and methods for accurately measuring leading edge and trailing edge media curls utilizing inclined array sensors. Array sensor (eg, contact image sensor (CIS) module) in which one or more curled media sheets (eg, paper, photographic media, printing medium, etc.) are inclined from the leading edge and / or trailing edge Or propeller in a process direction via a medium proppelling device (CCD). An inclined array sensor with a rotation vector in the cross-process direction can be disposed upstream or downstream of the media-propeling device at an angle to the media sheet exiting the curler to calculate the function of the sheet curl. The function of the sheet curl can be obtained by measuring the point at which the propped media sheet touches the array associated with the inclined array sensor. This curl measurement method enhances the accuracy and robustness against environmentally caused errors.

To determine each of the leading edge curl and / or trail edge curl functions, the curled media sheet enters the inclined array sensor on the left side and / or right side and proceeds through the media-propeling device. The system limits the edge of the curled media sheet so that the array sensor can accurately measure the sheet media curl. The points of the array sensor and the media sheet can be a function of sheet curl, array position, and angle. Each pixel with respect to the array sensor can be queried to detect the presence of a sheet edge. Optionally, a second array sensor can be added to measure the bidirectional curl relative to the media sheet. Such systems and methods allow multiple measurements of media curl to reduce noise and improve accuracy. In addition, the delivery methods and devices as discussed herein can limit the media in the vicinity of the disclosed tilted array sensor. Restriction or contact allows the array touch points to more accurately measure media curl.

1 illustrates a schematic diagram illustrating a curl measurement system equipped with an inclined array sensor, in accordance with disclosed embodiments.
2 is a graphical representation of a curl measurement system illustrating various curled media sheets touching an inclined array sensor at different locations, in accordance with disclosed embodiments.
3 illustrates a graph representing media sheet curls as a function of sensor measurement, in accordance with disclosed embodiments.
4 illustrates a schematic diagram illustrating a bidirectional curl measurement system associated with a pair of inclined array sensors, in accordance with disclosed embodiments.
5 illustrates a high level flow chart of operations illustrating logical operation steps of a method of measuring accurate media curl using a tilted array sensor, in accordance with disclosed embodiments.

The specific values and configurations discussed in these non-limiting examples can be changed, cited only to illustrate at least one embodiment, and are not intended to limit the scope thereof. Note that in the configuration illustrated here, the media sheets (also referred to simply as "medium") shown as entering (left to right) and exiting (right to left) are equivalent configurations. That is, the medium may enter to the left and exit to the right, enter to the right and exit to the left, or enter and exit to the left or right, depending on the design configurations and the type of rendering device utilized.

1 illustrates a schematic diagram illustrating a curl measurement system 100 equipped with an inclined array sensor 130, in accordance with disclosed embodiments. The curl measurement system 100 can be used to measure the media curls 132-138 with respect to one or more curled media sheets 150 to avoid paper jams and registration errors. The curl measurement system 100 can be implemented in connection with the measurement of the leading edge and / or trail edge position of the media sheet 150 in a marking engine, such as paper or transparency in a zero graphics rendering device. As utilized herein, it is noted that the term rendering device may refer to an apparatus or system, such as a printer, a fax machine, a copier, and / or combinations thereof.

System 100 generally includes an inclined array sensor 130 and transmission nips 110 and 120. The function of the transmission nips 110 and 120 with or without a potential upstream device is to limit the contact of the paper in the transmission nips. This improves the accuracy of the curl measurement. However, it should be understood that the transmission nips 110 and 120 are merely examples of how the sheets can be delivered to the inclined sensor. It can be appreciated that other devices and devices are possible. The transmission nips 110 and 120 may be positioned on opposite sides of the media path 160 to receive the media sheet 150 and drive towards the inclined array sensor 130. The term 'medium' generally refers to sheets of paper and is typically laminated, with transfer nips 110 and 120 pulling the top sheet out of the paper stack and delivering it to the rendering device. 150 may be described as having a leading edge that refers to the edge of the paper that exits the rendering device first, which is referred to as the trailing edge.

The curled media sheets 150 propel through the transmission nips 110 and 120 towards the inclined array sensor 130 from the leading edge and / or trailing edge to accurately measure the media curls 132-138. Can be. Note that the inclined array sensor 130 may be the same as a contact image sensor or charge couple device consisting of a series of linear pixels, for example, depending on design considerations. Contact image linear sensors (CIS) are photoelectric devices used to scan flat patterns or documents in electronic formats to provide easy storage, display, editing or delivery capabilities. The sensor reproduces the image shown on the document for the sensor pixels.

The contact image sensor is generally provided as a module consisting of a light source, a lens, and a sensor. This module is called a contact image sensor (CIS) module. CCD linear image sensors are utilized to convert optical images into electrical signals. CCD linear image sensors detect vertical charge-coupled devices (VCCD), horizontal charge-coupled devices (HCCD), and sensed image charges for delivering sensed image charges to external peripheral circuitry. It includes at least one of. It will be appreciated that other types of inclined array sensors may be utilized instead of the proposed sensor.

2 illustrates a graphical representation of curl measurement system 100 illustrating various curled media sheets 150 touching inclined array sensor 130 at different locations, according to the disclosed embodiment. 1-5, the same or similar parts are generally indicated by the same reference numerals. Curled media sheets 150 propel from the leading edge and / or trailing edge towards the inclined array sensor 130 in the process direction through the media proping device 170 associated with the transmission nips 110 and 120. Can be. The inclined array sensor 130 may be disposed upstream or downstream of the media-propeling device 170 at an angle to the media sheet 150 exiting the transmission nips 110 and 120 (eg, 15 °). Can be. Inclined array sensor 130 has a rotation vector in the cross process direction. The media sheet curl function may be obtained by measuring the point at which the propped media sheets 150 touch the array associated with the tilted array sensor 130 (eg, touch point).

The curled media sheet 150 enters the inclined array sensor 130 on the left side and / or the right side, and the media of the transmission nips 110 and 120 to determine the leading edge curl and / or trail edge curl functions, respectively. Proceed through the propeller device (s). System 100 limits the edge of curled media sheet 150 so that array sensor 130 can accurately measure sheet media curls 132-138. Each pixel with respect to array sensor 130 may be queried to detect the presence of a sheet edge. The media sheet 150 is limited to remain properly flat in the region x <0. The leading edge of the media sheet 150 may be allowed to assume its shape freely, ie for any portion of the sheet with coordinates x> 0. 2 shows media sheets 150 of various curl radii that assume a natural shape for x> 0.

3 illustrates a graph 300 representing sheet media curls 132-138 as a function of sensor measurements, in accordance with the disclosed embodiments. The touch points of the inclined array sensor 130 and the media sheet 150 may be a function of the sheet media curls 132-138, the array position, and the array angle. In graph 300, the x-axis represents the measurement of the x-coordinate of the point of contact with the array sensor 130, and the y-axis represents the measurement of the media curl 132-138 with respect to the media sheets 150. do. The sensor 130 may be queried from left to right and, in the first occurrence of "sheet present", denotes the x-coordinate. The sheet curl can be calculated for the sensor face geometry and the sheet curl radius R described by straight lines as follows.

(1)X =

(One)

(2)Y =

(2)

here,

d _x = x ₂ -x ₁ (3)

d _y = y ₂ - y ₁ (4)

(5) d _r =

(5)

(6) D =

(6)

(7)

(7)

Points (x ₁ , y ₁ ,) and (x ₂ , y ₂ ) represent the two end points of the rotation vector of the sensor array 130 with respect to the coordinate plane, and d _r represents the length of the sensor array rotation vector. Express. Equations (1) and (2) can determine the exact touch points of the inclined array sensor 130 and the medium 150. The curl measurement system 100 can measure the curls 132-138 of the medium 150 with high sensitivity, that is, with smaller sensor angles. This system and method allows multiple measurements of media sheet curls to reduce noise and improve accuracy.

4 illustrates a schematic diagram illustrating a bidirectional curl measurement system 400 associated with a pair of inclined array sensors 130, in accordance with the disclosed embodiments. The bidirectional curl measurement system 400 can be configured with the inclined array sensor 130 on each side of the media path 160 to measure both positive and negative curl associated with the media sheet 150. Note that the bidirectional measurement system 400 may not be necessary while measuring the unidirectional curl of the media sheet 150.

5 is a high level flow chart of operations illustrating logic operation steps of a method 500 for measuring accurate media sheet curl 132-138 utilizing an inclined array sensor 130, in accordance with disclosed embodiments. To illustrate. As indicated at block 510, one or more curled media sheets 150 may be propped in the process direction towards the inclined array sensor through a nip associated with the color. Next, as indicated at block 520, the inclined array sensor can be disposed at an angle to the media sheet 150 exiting or upstream and upstream of the media propeling device.

The inclined array sensor 130 is ideally suited for curl measurement because each pixel can be queried to detect the presence of the media sheet 150 edge. The function of the media sheet curls 132-138 can be obtained by measuring the touch point at which the propped media sheets 150 touch the array associated with the inclined array sensor 130, as indicated at block 530. . The correct sheet curl can then be determined utilizing the sheet curl function, as indicated in block 540. This approach provides accurate sheet curl (132-138) measurements to eliminate errors caused by edge movement due to air flow, machine vibration, edge flipping, and the like.

The delivery device may be upstream or downstream from the inclined array sensor described herein. In addition, the delivery method and / or device or system may be configured to limit the medium near the angle sensor. Restriction or contact makes the array touch point a more accurate measure of media curl.

Claims (9)

A method of measuring a media sheet curl,
Propellering at least one curled media sheet in the process direction through a media-proppelling device towards an angled array sensor, wherein the inclined array sensor is configured to produce a rotation vector in the cross-process direction. Propelling the at least one curled media sheet having; And
Measure the point at which the at least one curled media sheet touches the array associated with the inclined array sensor to obtain a function of sheet curl, thereby enhancing accuracy and robustness to environmentally caused errors. And measuring the media sheet curl. The method of claim 1,
Disposing the inclined array sensor at an angle to the media sheet exiting a curler and upstream or downstream of the media-propeling device to calculate a function of the sheet curl. How to measure sheet curls. The method of claim 1,
Limiting an edge of the curled media sheet to accurately measure the media sheet curl through the inclined array sensor. A system for measuring media sheet curls,
An inclined array sensor having a direction of rotation in a cross-process direction;
A media propeling device for propelling at least one curled media sheet in a process direction from an edge towards the inclined array sensor; And
A measurement device that measures the point at which the at least one curled media sheet touches the array associated with the inclined array sensor to obtain a function of sheet curl, thereby enhancing accuracy and robustness against environmentally induced errors. A system for measuring media sheet curl. The method of claim 4, wherein
The inclined array sensor is positioned at an angle to the media sheet exiting color to calculate a function of the sheet curl and upstream or downstream of the media-propeling device. The method of claim 4, wherein
Wherein each pixel on the array is queried with respect to the array sensor to detect the presence of a sheet edge. The method of claim 4, wherein
And a second inclined array sensor to assist in measuring the angular media curl. A system for measuring media sheet curls,
An inclined array sensor having a rotation vector in the cross process direction;
A media propeling device that propels at least one curled media sheet in a process direction from an edge toward the inclined array sensor, wherein the inclined array sensor exits the color to exit the color to calculate a function of sheet curl. The medium propeling device, positioned at an angle to and upstream or downstream of the medium propeling device; And
A measurement device that enhances the accuracy and robustness to environmentally induced errors by measuring the point at which the at least one curled media sheet touches the array associated with the inclined array sensor to obtain a function of the sheet curl A system for measuring media sheet curl comprising a. The method of claim 8,
The edge of the curled media sheet is constrainable to accurately measure the media sheet curl via the inclined array sensor,
The sheet curl is measurable when the at least one curled media sheet enters the inclined array sensor from a leading edge,
And the sheet curl is measurable when the at least one curled media sheet enters the inclined array sensor from a trailing edge.

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